1. Field of the Invention
The present invention relates to a washing machine, and more particularly to a washing machine of a drum type with an air bubble generator capable of evenly dispersing air bubbles throughout washing water in a washer tub.
2. Description of the Prior Art
In general, the washing machines are classified into two categories. The first one of the two categories includes a whirl-type washing machine in which washing articles are washed by a vortex flow of washing water formed in a washer tub when a pulsator is rotated. The second one includes a drum-type washing machine. The drum-type washing machine has a rotary drum a portion of which lies in the washing water. In such a rotary drum, the washing articles are put in the rotary drum. When the rotary drum is rotated, the washing articles in the rotary drum strike each other, so that the washing articles are washed.
In order to enhance washing efficiency of the drum-type washing machine, an air bubble generator for the drum-type washing machine is proposed. FIG. 1 is a schematic view of a conventional drum-type washing machine with an air bubble generator, FIG. 2 is an enlarged perspective view of the rotary drum of FIG. 1, and FIG. 3 is an enlarged perspective view of the air bubble generator of FIG. 1.
Hereinafter, the conventional drum-type washing machine with an air bubble generator will be described with reference to accompanying drawings.
In general, a drum-type washing machine includes a housing (10) and a washer tub mounted in the housing (10) to accommodate washing water. The shaft (not shown) of the rotary drum (30) is mounted parallel to the surface of the washing water. A portion of the rotary drum (30) is sunk in the washing water. The rotary drum (30) has a plurality of through-holes (32). The through-holes (32) are formed in a certain pattern for the washing water to flow in and out of the rotary drum (30).
The surface of the rotary drum (30) is formed with four backward curved vane-type latches (34). Each of the four backward curved vane-type latches (34) has a latch surface (36) which continuously increases its height in a radial direction forwardly from the beginning to the end of the latch surface (36). The four backward curved vane-type latches (34) are each spaced apart in a certain distance along the surface of the rotary drum (30). The end of the latch surface (36) has two plate-shaped latch edges (37) at both side ends protruding in a radial direction. A slit between the two latch edges (37) is formed to backwardly decrease its height in a radial direction, and the slit is wide enough for air bubbles to pass through and into the rotary drum (30) from the washing water.
The air bubble generator (40) is disposed over the bottom of washer tub and connected with an air pump (not shown) through a conduit (42). The air bubble generator (40) is operated to supply a certain amount of air bubbles periodically and at one time into the rotary drum (30). The air bubble generator (40) is completely sunk in the washing water. As shown in FIG. 3, the air bubble generator (40) is constituted with a coverless box-type case (44) and an air bubble-generating plate (48). The air bubble-generating plate (48) covers the box-type case (44), to thereby form space between them. The case (44) prevents air flowing in through the conduit (42) from flowing out of the air bubble generator (40) except through the air bubble-generating plate (48). An inlet (45) with which the conduit (42) is connected is provided in the bottom of the case (44). A porous member (46) is mounted between the case (44) and the air bubble-generating plate (48). The air bubble-generating plate (48) has a plurality of through-holes (49) for supplying air bubbles into the washing water. The plurality of through-holes (49) are small enough in diameter for an air bubble to maintain its shape.
Hereinafter, operations of a conventional air bubble generator as mentioned above will be described.
The porous member (46) in the case (44) under the washing water passes air flowing in through the inlet (45) onto the air bubble-generating plate (48). The air bubbles from the air bubble-generating plate (48) go up directly through the porous member (46). Only a small amount of air bubbles from the porous member (46) passes through the through-holes (49) onto the rotary drum (30). However, most of the air bubbles from the porous member (46) move along the lower side of the air bubble-generating plate (48) into the sides thereof because of a water membrane formed in each of the through-holes (49). The air, from the air bubbles, gathered under the sides of the air bubble-generating plate (48) is stuck by the sides of the case (44) and passes through the porous member (46) and the air bubble-generating plate (48) toward the rotary drum (30). The air bubbles from the through-holes (49) flow into the washing water in the rotary drum (30) through the slit (38) as the rotary drum (30) is rotated. The air bubbles in the washing water serve to wash washing articles.
However, in the conventional air bubble generator, more air bubbles are generated from the sides of the air bubble-generating plate compared to those from the air bubble-generating plate except the sides. Accordingly, the amount of air bubbles does not flow evenly in the rotary drum as the rotary drum is rotated, to thereby reduce washing efficiency.
Further, in a washing machine with the conventional air bubble generator, since the rotary drum is mounted far apart from the sides of the air bubble generator, the air bubbles are likely to disappear in the washing water before reaching the rotary drum.